1. Field of the Invention
The invention relates to a dilating apparatus for widening a puncture channel in the kidney, of the type wherein a series of catheters of increasing diameter are used to widen a puncture channel formed initially with a puncture needle.
2. Description of the Prior Art
For examination of kidneys and for percutaneous removal of kidney stones by means of an operational nephroscope, a puncture channel is first made in the kidney by means of a puncture needle, a guiding wire extending through the needle having its distal extremity left in the channel after withdrawal of the needle and subsequently acting as a guide for a guiding tube comprising a distal stop and intended to guide the first catheter widening the puncture. After the first catheter, the other catheters are guided consecutively over the guiding tube and utilised for additional widening of the puncture channel.
After the puncture channel has been widened, a nephroscope is inserted into the kidney along the guiding wire and the guiding wire is then removed. In some circumstances the nephroscope may be caused by handling actions during stone disintegration to leave the puncture channel accidentally so that it is then very difficult to rediscover the puncture in the kidney without a guiding wire. For this reason, a narrow nephroscope shaft was brought into use beside the existing catheters during catheterising, which is traversed by a second guiding wire which extends beside the catheters and beside the nephroscope during insertion of additional catheters and of the nephroscope and provides a safety feature by virtue of the fact that it may be utilised as a guide for the nephroscope if the first guiding wire were to be pulled accidentally out of the puncture channel of the kidney.